Dial Pulse Counter and Hook Status Monitor
• Time-guarded dial pulse counting
• 10 or 20 PPS dialing speeds pin selectable
• Tri-state data outputs
• Valid data output strobe
• Data strobe control for use in interrupt-driven
• Independent hook status monitoring
• Low-power CMOS construction
The M-959 is a low-power dial pulse counter and
hook status monitor. Contained in a 14-pin package,
the M-959 requires no external components except a
single 3.579 MHz television color burst crystal.
The M-959 is typically connected to a loop current
sensing circuit, which is connected in series with the
voice pair (Tip and Ring) of a telephone line. The M-
959 receives pulses from the loop current sense cir-
cuit and translates them into logic level outputs
indicating hook status and decoded dialed digits.
Logic inputs to the M-959 select dialed digit speeds
and control Data and Strobe outputs supporting bus
interrupt driven implementations.
14-pin plastic DIP